Abstract Schizophrenia remains one of the most disabling conditions world-wide with an economic burden that exceeded $155 billion dollars in fiscal year 2013 alone. Despite existing medication and community treatment, many individuals with this diagnosis continue to have poor outcomes and struggle toward recovery. CAT is a psychosocial treatment using environmental supports such as signs, alarms, pill containers, checklists, technology and the organization of belongings established in a person's home or work environment to bypass the cognitive and motivational difficulties associated with schizophrenia, and support habits for functional behavior to promote recovery. In a series of efficacy studies, CAT improved social and occupational functioning, symptoms, and adherence to medication, and reduced rates of readmission. We propose a cluster randomized effectiveness trial comparing Cognitive Adaptation Training (CAT) to existing community treatment (CT) for individuals with schizophrenia in 8 community mental health centers across multiple states including 400 participants. This would be the first large-scale effectiveness study of CAT for improving functional outcomes for those with schizophrenia seen in community mental health centers (CMHCs) where the majority of those with schizophrenia are followed for outpatient care and to study the purported mechanisms of action based on an integrated theoretical model. Participants will be assessed at baseline and 6 and 12 months on measures of functional and community outcome, medication adherence, symptoms, habit formation and automaticity, cognition and motivation. CAT treatment will be weekly for 6 months, biweekly for 3 months and monthly for the remainder of the trial. Purported mechanisms of action for CAT including bypassing impairments in cognitive function to improve functional outcome and bypassing motivational impairments to create automatic habits to improve functional outcome will be examined.